Fri, 15 Feb 2019 10:38:39 -0800WeeblyTue, 10 May 2016 01:39:31 GMThttp://www.sparkantiqueradioclub.com/tech-talk/extending-a-potentiometer-shaftThe following YouTube video demonstration provided by Ed App shows how to extend a potentiometer shaft when a longer shaft is necessary in the event a replacement is needed but the proper size isn't available.

Got a globe O1A tube for a 1920s battery set that is weak? Here's what you can do: "rejuvenate" the tube!

Here's the procedure:1. Make sure there are no shorts.2. Hook up the two big pins (filament) to your DC variable power supply.3. Crank up the voltage to 12 Volts. Ordinarily an O1A runs at 5 Volts however, giving it 12 Volts makes it glow brightly like a light bulb. Do this for 5 minutes.4. After those 5 minutes, reduce the filament voltage to 5 Volts. What I do is "cook" the tube overnight.5. Check the O1A the next morning and you will have a good usable tube. Check it on your tube checker, you will be pleased.

*Note: Don't check the tube immediately after applying the 12 Volts. You will get no emission reading at all! The tube must "cook" for at least four to five hours at 5 Volts first.